Developers always need model, so we try our best to make as many free model as we can and hope they might help you!
New products are available every week, we kindly invite you to visit 3d4ya.com frequently to check them out!
Sorry if you find it annoying.

the file formats you have available may be more common on pc development, but if you want mac users to consider your models you will need ( obj, fbx, c4d ) possibly .ma, but mostly .obj since it can be opened nearly on any app.